LM337
Three-terminal adjustable negative voltage regulators
Datasheet - production data
current limit, thermal overload protection and safe
area protection. All overload protection circuitry
remains fully functional even if the adjustment
terminal is disconnected.
Table 1. Device summary
Temperature
Order codes Packages
range
LM337SP TO-220 0 °C to 125 °C
TO-220
Features
• Output voltage adjustable down to VREF
• 1.5 A guaranteed output current
• 0.3%/V typical load regulation
• 0.01%/V typical line regulation
• Current limit constant with temperature
• Ripple rejection: 77 dB
• Standard 3-lead transistor packages
• Excellent thermal regulation: 0.002%/V
• 50 ppm/°C temperature coefficient
Description
The LM337 series are adjustable 3-terminal
negative voltage regulators capable of supplying
in excess -1.5 A over a -1.2 to -37 V output
voltage range. They are exceptionally easy to use
and require only two external resistors to set the
output voltage. Further, both line and load
regulation are better than standard fixed
regulators. Also, LM337 regulators are supplied in
standard transistor packages which are easily
mounted and handled. In addition to higher
performance than fixed regulators, the LM337
series offer full overload protection available only
in integrated circuits. Included on the chip are
May 2014 DocID2167 Rev 5 1/17
This is information on a product in full production. www.st.com
Contents LM337
Contents
1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Thermal regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7 Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
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LM337 Diagram
1 Diagram
Figure 1. Schematic diagram
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Pin configuration LM337
2 Pin configuration
Figure 2. Pin connections (top view)
TO-220
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LM337 Maximum ratings
3 Maximum ratings
Table 2. Absolute maximum ratings
Symbol Parameter Value Unit
V I - VO Input output voltage differential 40 V
IO Output current 1.5 A
PD Power dissipation Internally limited
TSTG Storage temperature range - 65 to 150 °C
TOP Operating junction temperature range 0 to 125 °C
Note: Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
Table 3. Thermal data
Symbol Parameter TO-220 Unit
RthJC Thermal resistance junction-case max. 3 °C/W
RthJA Thermal resistance junction-ambient max. 70 °C/W
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Electrical characteristics LM337
4 Electrical characteristics
TJ = 0 to 150 °C VI - VO = 5 V, IO = 0.5 A unless otherwise specified.
Table 4. Electrical characteristics
Symbol Parameter Test conditions Min. Typ. Max. Unit
Ta = 25°C -1.213 -1.25 -1.287
VREF Reference voltage |VI - VO| = 3 to 40 V, TJ = Tmin to Tmax V
-1.2 -1.25 -1.3
|IO| = 10mA to |IO(max)|, P ≤ Pmax
Ta = 25°C IO = 0.1 A 0.01 0.04
KVI Line regulation (1) %/V
|VI - VO| = 3 to 40 V IO = 20 mA 0.01 0.04
Ta = 25°C |VO| ≤ 5 V 15 50 mV
KVO Load regulation (1)
|IO| = 10mA to |IO(max)| |VO| ≥ 5 V 0.3 1 %
Thermal regulation Ta = 25°C, pulse 10 ms 0.003 0.04 %/W
IADJ Adjustment pin current 65 100 µA
Adjustment pin current Ta = 25°C, |IO| = 10 mA to |IO(max)|
ΔIADJ 2 5 µA
change |VI - VO| = 3 to 40 V
KVI Line regulation (1) |VI - VO| = 3 to 40 V 0.02 0.07 %/V
|VO| ≤ 5 V 20 70 mV
KVO Load regulation (1) |IO| = 10mA to |IO(max)|
|VO| ≥ 5 V 0.3 1.5 %
|VI - VO| ≤ 40 V 2.5 10
|IO(min)| Minimum load current mA
|VI - VO| ≤ 10 V 1.5 6
|VI - VO| ≤ 15 V 1.5 2.2
IOS Short circuit output current A
|VI - VO| = 40 V, TJ =2 5°C 0.15 0.4
RMS output noise
VNO Ta = 25°C, f = 10 Hz to 10 kHz 0.003 %
(% of VO)
VO = -10 V, f = 120 Hz 60
RVF Ripple rejection ratio dB
CADJ = 10 µF 66 77
KVT Temperature stability 0.6 %
KVH Long term stability Ta = 125°C, 1000 H 0.3 1 %
1. Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output
voltage due to heating effects are covered under the specification for thermal regulation.
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LM337 Typical characteristics
5 Typical characteristics
Figure 3. Load regulation Figure 4. Current limit
Figure 5. Adjustment current Figure 6. Dropout voltage
Figure 7. Temperature stability Figure 8. Minimum operating current
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Typical characteristics LM337
Figure 9. Ripple rejection vs. output voltage Figure 10. Ripple rejection vs. frequency
Figure 11. Ripple rejection vs. output current Figure 12. Output impedance
Figure 13. Line transient response Figure 14. Load transient response
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LM337 Thermal regulation
6 Thermal regulation
When power is dissipated in an IC, a temperature gradient occurs across the IC chip
affecting the individual IC circuit components. With an IC regulator, this gradient can be
especially severe since power dissipation is large.
Thermal regulation is the effect of these temperature gradients on output voltage (in
percentage output change) per watt of power change in a specified time. Thermal regulation
error is independent of electrical regulation or temperature coefficient, and occurs within 5
ms to 50 ms after a change in power dissipation. Thermal regulation depends on IC layout
as well as electrical design. The thermal regulation of a voltage regulator is defined as the
percentage change of VO, per watt, within the first 10ms after a step of power, is applied.
In Figure 1, a typical LM337’s output drifts only 3 mV for 0.03% of VO = – 10 V) when a 10 W
pulse is applied for 10 ms. This performance is thus well inside the specification limit of
0.02%/W x 10 W = 0.2% max. When the 10 W pulse is ended the thermal regulation again
shows a 3 mV step as the LM337 chip cools off. Note that the load regulation error of about
8 mV (0.08%) is additional to the thermal regulation error.
In Figure 2, when the 10 W pulse is applied for 100 ms, the output drifts only slightly beyond
the drift in the first 10 ms and the thermal error stays well within 0.1% (10 mV).
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Typical application LM337
7 Typical application
Figure 15. Adjustable negative voltage regulator
* C1 = 1 µF solid tantalum or 10 µF aluminium electrolytic required for stability.
** C2 = 1 µF solid tantalum is required only if regulator is more than 10 cm from power supply filter capacitors
Figure 16. Adjustable lab voltage regulator
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LM337 Typical application
* The 10 µF capacitors are optimal to improve ripple rejection.
Figure 17. Current regulator
Figure 18. Negative regulator with protection diodes
* When CL is larger than 20 µF, D1 protects the LM337 in case the input supply is shorted.
** When C2 is larger than 10 µF and VO is larger than - 25 V, D2 protects the LM337 in case the output is
shorted.
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Typical application LM337
Figure 19. - 5.2 V regulator with electronic shutdown (1)
1. Minimum output = - 1.3 V when control input is low.
Figure 20. Current regulator
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LM337 Package mechanical data
8 Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
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Package mechanical data LM337
Figure 21. TO-220 (dual gauge) drawing
BW\SH$B5HYB7
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LM337 Package mechanical data
Table 5. TO-220 mechanical data
mm
Dim.
Min. Typ. Max.
A 4.40 4.60
b 0.61 0.88
b1 1.14 1.70
c 0.48 0.70
D 15.25 15.75
D1 1.27
E 10 10.40
e 2.40 2.70
e1 4.95 5.15
F 1.23 1.32
H1 6.20 6.60
J1 2.40 2.72
L 13 14
L1 3.50 3.93
L20 16.40
L30 28.90
∅P 3.75 3.85
Q 2.65 2.95
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Revision history LM337
9 Revision history
Table 6. Document revision history
Date Revision Changes
19-Jul-2004 1 First issue.
10-Jan-2005 2 Modified pin connection for TO-3.
17-Jul-2008 3 Added: Table 1 on page 1.
03-Oct-2011 4 Modified: Table 1 on page 1.
The part number LM137 has been moved to a separate datasheet.
Removed TO-3 package.
Updated the description in cover page.
05-May-2014 5 Modified Table 1: Device summary, Section 2: Pin configuration, Section 3:
Maximum ratings, Section 4: Electrical characteristics, Section 6: Thermal
regulation and Section 8: Package mechanical data.
Minor text changes.
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LM337
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